Crate asm_rs 

asm-rs — Pure Rust Multi-Architecture Assembly Engine

asm-rs is a pure Rust, zero-C-dependency, multi-architecture runtime assembler that turns human-readable assembly text into machine-code bytes.

Quick Start

use asm_rs::{assemble, Arch};

let code = assemble("nop", Arch::X86_64).unwrap();
assert_eq!(code, vec![0x90]);

Features

• Pure Rust — no C/C++ FFI, no LLVM, no system assembler at runtime.
• Multi-arch — x86, x86-64, ARM, AArch64, RISC-V (feature-gated).
• Runtime text parsing — assemble from strings at runtime.
• no_std + alloc — embeddable in firmware, kernels, WASM.
• Labels & branch relaxation — automatic forward/backward label resolution.

Re-exports

pub use assembler::Assembler;

pub use assembler::AssemblyResult;

pub use assembler::ResourceLimits;

pub use encoder::RelocKind;

pub use error::ArchName;

pub use error::AsmError;

pub use error::Span;

pub use ir::AddrMode;

pub use ir::AlignDirective;

pub use ir::Arch;

pub use ir::BroadcastMode;

pub use ir::ConstDef;

pub use ir::DataDecl;

pub use ir::DataSize;

pub use ir::DataValue;

pub use ir::Expr;

pub use ir::FillDirective;

pub use ir::Instruction;

pub use ir::MemoryOperand;

pub use ir::Mnemonic;

pub use ir::Operand;

pub use ir::OperandList;

pub use ir::OperandSize;

pub use ir::OptLevel;

pub use ir::OrgDirective;

pub use ir::Prefix;

pub use ir::PrefixList;

pub use ir::Register;

pub use ir::SpaceDirective;

pub use ir::Statement;

pub use ir::SvePredQual;

pub use ir::Syntax;

pub use ir::VectorArrangement;

pub use ir::X86Mode;

pub use linker::AppliedRelocation;

pub use preprocessor::Preprocessor;

Modules

assembler

Public assembler API — builder pattern, one-shot assembly, and AssemblyResult. Public assembler API — builder pattern and one-shot assembly.

encoder

x86-64 instruction encoder (REX, ModR/M, SIB, immediate, relocation). x86-64 instruction encoder.

error

Error types and source-span diagnostics. Error types and source span tracking for diagnostics.

ir

Intermediate representation: registers, operands, instructions, directives. Intermediate representation types for the assembly pipeline.

lexer

Zero-copy lexer (tokenizer) with span tracking. Lexer for assembly source text.

linker

Fragment-based linker: label resolution, branch relaxation, patching. Label resolution, branch relaxation, and final layout.

optimize

Peephole optimizations for instruction encoding. Peephole optimizations for x86/x86-64 instructions.

parser

Intel-syntax parser producing IR statements. Multi-architecture assembly parser.

preprocessor

Preprocessor: macros, repeat loops, and conditional assembly. Preprocessor for assembly source text.

Functions

assemble

Assemble a string of assembly into machine code bytes.

assemble_at

Assemble with an explicit base virtual address.

assemble_with

Assemble with external labels pre-defined at known addresses.